Wax-based compositions, articles made therefrom, and methods of manufacture and use

ABSTRACT

Wax-based compositions for making barrier layers used in oral treatment devices are thermally stable when formed into a flat sheet or three-dimensional article to a temperature of at least 45° C. and are plastically deformable at room temperature (25° C.). The wax-based compositions include a wax fraction homogeneously blended with a polymer fraction. The wax fraction includes at least one wax and the polymer fraction includes at least one polymer selected such that, when the at least one wax and at least one polymer are homogeneously blended together, they yield a wax-based composition having the desired properties of thermal stability and plastic deformability. Barrier layers in oral treatment devices made from such wax-based compositions are dimensionally stable to a temperature of at least 40° C. without external support and can be plastically deformed in a user&#39;s mouth to become at least partially customized to the size and shape of user&#39;s unique dentition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a 371 Application of International PatentApplication No. PCT/US2014/022032, filed Mar. 7, 2014, which claims thebenefit of U.S. Provisional Patent Application No. 61/775,453, filedMar. 8, 2013, and U.S. Provisional Patent Application No. 61/799,532,filed Mar. 15, 2013.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention is in the field of wax-based compositions anddental treatment devices and other articles made from such compositions.

2. The Relevant Technology

Dental treatment trays and strips are commonly used to deliver bleachingcompositions and medicaments to a user's teeth. “Trays” are pre-shapedbarriers designed to fit over some or all of a user's teeth and can becustomized or non-customized. Trays can be pre-loaded with an oraltreatment composition or filled with a treatment composition by the userat the time of use. “Strips” are generally non-customized sheet-likebarriers that include a treatment composition on one side or embeddedwithin the barrier layer and which can be placed over and folded arounda user's teeth in a tray-like configuration.

One type of customized dental tray is made by thermoforming a sheet ofmoisture-resistant thermoplastic polymer material, such as ethylenevinyl acetate copolymer (EVA), over a stone model of a user's teeth andthen trimming the intermediate molded form to yield the desiredtray-like shape. A blockout material can be applied to the stone modelto form reservoirs in the customized tray, which can accommodateplacement of additional treatment composition next to a person's toothsurfaces. Reservoirs can provide additional comfort by reducingorthodontic forces, particular with more rigid trays. Drawbacks ofcustomized trays formed in this manner include the time and cost offorming an impression of a person's teeth, typically at a dentistoffice, using the impression to form the stone model, thermoforming thesheet, and trimming the molded form to yield the customized tray. Themain benefit is that such trays typically provide the best fit, comfortand effectiveness in delivering a medicament to a user's teeth ascompared to oral strips and other types of dental trays.

Another type of customized tray is made using a person's own teeth asthe template (e.g., so called “boil-and-bite” trays). In a typicalcustomization process a non-customized tray blank made from a thermallysoftenable polymer material is initially heated (e.g., in hot water ormicrowave oven) to temporarily soften the polymer tray material. Thesoftened tray is then placed over the user's teeth and custom-formed tothe user's teeth using forces applied by one or more of biting,suctioning, or externally applied pressure using fingers. When thecustomized tray has cooled sufficiently to retain its form, it can beremoved from the user's mouth and is then ready for use. A drawback ofself-customized trays is that they can be bulky and uncomfortable,particularly when in the form of sports mouth guard, which typicallyhave a wall thickness of at least 3 mm and usually more. And while therehave been patents directed to thin-walled, self-customizable trays, suchtrays can be difficult for a non dental practitioner to use, have poorfit, and have had little market acceptance.

Non-customized trays lack features corresponding to a user's uniquedentition but can be made to roughly approximate the size and shape of avariety of differently sized and shaped dental arches. A major drawbackof non-customized trays is poor fit. Thicker walled trays can be bulky,uncomfortable and often have large gaps between the side walls and theuser's tooth surfaces. Thinner, more flexible trays can better adapt tothe shape of a user's teeth but have their own drawbacks. The thinnestand most comfortable of such trays can be flimsy and difficult toinstall and are more easily dislodged during use compared tocustom-fitted trays or more rigid non-customized trays. Thin-walledtrays made from materials that are sufficiently rigid and/or resilientso as to better maintain their tray-like shape and facilitateinstallation over a user's teeth tray are less adaptable and have traywalls that are more likely to pull away from a user's teeth during use,particularly the lingual wall. This can be both annoying to the user andpermit ingress of saliva into the trough, which can cause diffusion oftreatment composition into the person's oral cavity.

Conventional dental treatment strips typically comprise a flexibleplastic barrier layer coated or impregnated with a treatment compositionon the side of the strip facing the user's teeth. To install the strip,a portion of the strip is placed over the front surfaces of the user'steeth and the remainder is folded around the occlusal edges of the teethand against the lingual surfaces. A drawback of strips is that they aregenerally more difficult to install over a user's teeth in the properlocation compared to trays, which already have a trough into which theteeth are to be placed, which directs correct installation.Nevertheless, a properly placed strip can remain in place and provide ahigh level of comfort during treatment, perhaps even more comfort than adental tray. An improperly placed strip, however, can fail to properlycover all tooth surfaces to be treated, may require adjustment, and canpermit treatment composition to rapidly diffuse into the user's oralcavity. Moreover, strips with less adhesive treatment compositions areprone to slip off the teeth during use as a result of even minimalmovement of the user's mouth, jaw or tongue. It is usually recommendedthat users not eat, drink, smoke or sleep while wearing the treatmentstrip. In some cases, the strip can become so dislodged or mangled thatit must be removed and replaced with a fresh strip to complete thedesired treatment.

Ultimately, the main impediment to successful treatment is the failureof a user to complete the prescribed treatment regimen. If the treatmentapparatus is uncomfortable to wear, difficult to install and/or is proneto prematurely dislodge from the user's teeth, the user may simply giveup and prematurely abort the prescribed regimen. Thus, even if dentaltreatments are possible using a particular treatment apparatus ormethod, they are less likely to be properly completed if theinadequacies of the treatment apparatus or method cause a user to becomediscouraged before the desired results are attained.

BRIEF SUMMARY

Disclosed herein are wax-based compositions suitable for making sheetsor articles that are thermally stable and plastically deformable.Example wax-based compositions include a wax fraction comprised of atleast one wax and a polymer fraction homogeneously blended with the waxfraction comprised of at least one polymer. According to one embodiment,the wax-based composition is plastically deformable at room temperature(25° C.) and thermally stable when formed into a flat sheet orthree-dimensional article to a temperature of at least 40° C., or atleast about 42.5° C., or at least about 45° C., or at least about 48°C., or at least about 50° C., or at least about 52.5° C., or at leastabout 55° C., or at least about 60° C., or at least about 65° C., or atleast about 70°.

Also disclosed is a method of manufacturing a wax-based composition thatis suitable for making sheets or articles that are thermally stable andplastically deformable, wherein the method comprises: (1) combining aleast one wax and at least one polymer to form a mixture; and (2)processing the mixture to form a wax-based composition (a) that iscomprised of a wax fraction homogeneously blended with a polymerfraction, (b) that is thermally stable when formed into a flat sheet orthree-dimensional article to a temperature of at least 45° C., and (c)that is plastically deformable at room temperature (25° C.).

Flat sheets and three-dimensional articles made from wax-basedcompositions as disclosed herein can be used for any desired use, anexample of which is as a barrier layer forming part on oral treatmentdevice. According to one embodiment, the barrier layer can be in theform of a dental treatment tray having at least one side wall and atleast one bottom wall extending laterally from the at least one sidewall. According to another embodiment, the barrier layer can be in theform of a strip. The oral treatment devices include an oral treatmentcomposition that includes one or more active agents for providing adesired oral treatment.

According to one embodiment, barrier layers made from wax-basedcompositions are non-customized and devoid of features corresponding touser's unique dentition. Because of the unique properties of wax-basedcompositions disclosed herein, the barrier can be at least partiallycustomizable when placed into the user's mouth and heated to bodytemperature so as to at least partially conform to the user's uniquedentition, particularly the occlusal surfaces. In this way, the oraltreatment device can be self-customized by a user during use. Thiseliminates the need to first perform a customization procedure prior toplacing an oral treatment composition adjacent to the barrier layer inorder to obtain a device that closely conforms to a user's uniquedentition so as to function as an at least partially customized oraltreatment device. And to the extend the wax-based composition formingthe barrier layer is not elastic but is plastically deformable, once thetray is fitted over a user's teeth there is less likelihood that thebarrier layer will pull away from the user's teeth, as often occurs inthe case of flexible barrier layers made from a resilient and/orelastomeric material.

These and other advantages and features of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by references to specific embodiments thereof, which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings, in which:

FIGS. 1A-1B illustrate exemplary oral treatment devices that include adental treatment tray and a gel or solid oral treatment compositionwithin the tray;

FIGS. 2A-2B illustrate exemplary oral treatment devices that include adental treatment tray having features that assist the treatment devicein conforming to the shape of a user's dental arch and a gel or solidoral treatment composition within the tray;

FIGS. 3A-3B illustrate exemplary oral treatment devices that include adental treatment tray with cuts or discontinuities that assist thetreatment device in conforming to the shape of a user's dental arch anda gel or solid oral treatment composition within the tray

FIGS. 4A-4B illustrate oral treatment devices contained within sealedprotective packages having a peelable cover;

FIGS. 5A-5B illustrate an oral treatment device that includes a barrierlayer in the form of an initially flat strip coated with an oraltreatment composition;

FIGS. 6A-6B illustrate an oral treatment strip wrapped around andclosely conforming to the shape of a user's teeth as a result of thehighly adaptive nature of the wax-based barrier layer and adhesivenature of the oral treatment composition; and

FIGS. 7A-7E illustrate various shapes of strip-like barrier layers thatcan be used in fashioning oral treatment devices according to theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Introduction

Disclosed herein are wax-based compositions formed from a wax componentand a polymer component so as to be both thermally stable andplastically deformable. Because the wax-based compositions are thermallystable, articles made therefrom are able to maintain their shape withoutsignificant deformation (i.e., are dimensionally stable) in the absenceof external forces when heated to temperatures at which such articlesmay be exposed. Because the wax-based compositions are plasticallydeformable, articles made therefrom are able to be plastically deformedby application of a deformation force.

Also disclosed are methods of manufacturing wax-based compositions fromone more types of wax, one or more types of polymers, and optionally oneor more auxiliary components so as to have desired materials and/ormechanical properties. The one or more types of wax and one or moretypes of polymers can be homogeneously blended together to formwax-based compositions containing a wax fraction and a polymer fraction.Heat and/or pressure can be applied to yield a wax-based compositionhaving the desired materials and/or mechanical properties.

Example articles that can be made from wax-based compositions asdisclosed herein include sheets and three-dimensional forms. The sheetsand three-dimensional articles can be thermally stable and plasticallydeformable. The sheets can be used for any desired purpose, examples ofwhich include as a barrier layer in an oral treatment strip used toapply an oral treatment composition to a user's teeth and/or gums, as anintermediate substrate that is thermoformed into a dental treatmenttray, and as a covering for reversibly sealing an orifice of acontainer. Examples of useful three-dimensional articles include dentaltreatment trays, such as those made by injection molding the wax-basedcomposition or thermoforming a wax-based sheet.

Oral treatment devices are an example of a specific application ofexample articles made from wax-based compositions as disclosed herein.Oral treatment devices can include a barrier layer, such as a strip ortray, and one or more oral treatment compositions adjacent to and/orimpregnated within the barrier layer. An example oral treatment stripincludes a wax-based sheet that is initially flat and includes an oraltreatment composition adjacent to and/or impregnated within the sheet.The oral treatment strip can be placed over and wrapped around at leasta portion of a user's teeth. Another example of an oral treatment deviceincludes a preformed dental treatment tray formed from a wax-basedcomposition and an oral treatment composition placed and/or impregnatedwithin the dental treatment tray. The preformed dental treatment trayfacilitates greater ease of placement of the oral treatment device overa person's teeth compared to an oral treatment strip.

According to one embodiment, an oral treatment device includes a barrierlayer that is initially non-customized and devoid of featurescorresponding to a user's unique dentition but which can adapt to theperson's teeth during use. According to one embodiment, the barrierlayer is at least partially customizable when warmed to body temperatureand shaping forces are applied, such as suctioning, biting and/or fingerpressure. In this way, a self-customizable oral treatment device isprovided that can be self-customized in a user's mouth after placementof an oral treatment composition on or in the barrier layer. Thisgreatly facilitates oral treatment because it provides a comfortablefitting, customized device that can be made during oral treatment. Thiseliminates cumbersome customization procedures and time delays typicallyinvolved in making customized trays, whether using a stone model of aperson's teeth or in a “boil and bite” procedure. Customization hasheretofore required customization prior to applying the oral treatmentcomposition on or in a customized dental tray. The ability of oraltreatment devices that already include a treatment composition to beself-customized in the user's mouth is surprising and unexpected, whichfurther emphasizes the unique and inventive nature of wax-basedcompositions as disclosed herein.

Kits are also provided that utilize barrier layers made from wax-basedcompositions as disclosed herein and oral treatment devices that includebarrier layers and one or more oral treatment compositions adjacent toor impregnated within the barrier layer. Kits may include multiple oraltreatment devices that include a barrier layer and one or morepre-applied oral treatment compositions. Alternatively, kits may includeone or more oral treatment devices that include a barrier layer and oneor more oral treatment compositions that can be applied to the barrierlayer by a user.

Methods of providing treatment to a user's teeth and/or gums utilizebarrier layers made from wax-based compositions as disclosed herein andone or more oral treatment compositions that are pre-applied to thebarrier layer or which can be applied to the barrier layer by a user atthe time of use. According to one embodiment, a user places an oraltreatment device that includes a wax-based barrier layer and an oraltreatment composition into the user's mouth and then plastically deformsthe wax-based barrier layer to better conform to the user's uniquedentition in order to provide better fit and comfort. The oral treatmentdevice can be self-customizable by the user as described herein, such asby warming the wax-based barrier layer to body temperature within theuser's mouth and applying forces to plastically deform the barrier layerin order to at least partially customize the barrier layer so as toinclude indentations that conform to the user's unique dentition.

II. Wax-Based Compositions

Wax-based compositions as disclosed herein include a wax fraction, apolymer fraction homogeneously blended with the wax fraction, andoptionally one or more auxiliary components. Examples of waxes that canbe used include petroleum waxes, distilled waxes, synthetic waxes,mineral waxes, vegetable waxes, and animal waxes. Examples of polymersthat can be used include synthetic and natural polymers. Examples ofauxiliary components include plasticizers, flow modifiers, and fillers.

Examples of petroleum waxes include paraffin waxes (made of long-chainalkane hydrocarbons) (e.g., IGI 1260A), intermediate waxes (blend oflong-chain and branched alkanes), microcrystalline waxes (branchedalkane hydrocarbons of higher molecular weight and more amorphous thanparaffin waxes) (e.g., IGI 5909A), distilled waxes (e.g., Astorstat®distilled waxes, such as Astorstat 6988, Astorstat 6920, 10069,Astorstat Astorstat 95, Astorstat 90, Astorstat 75, and Astorstat10316), and petroleum jelly. Examples of synthetic waxes includepolyethylene waxes (based on polyethylene), Fischer-Tropsch waxes (madefrom synthesis gas), chemically modified waxes (which are usuallyesterified or saponified), substituted amide waxes, and polymerizedα-olefins. Examples of mineral waxes include ceresin waxes, montan wax(extracted from lignite and brown coal), ozocerite (found in lignitebeds), and peat waxes. Examples of vegetable waxes include bayberry wax(from the surface wax of the fruits of the bayberry shrub, Myrica faya),candelilla wax (from the Mexican shrubs Euphorbia cerifera and Euphorbiaantisyphilitica), carnauba wax (from the leaves of the Carnauba palm,Copernica cerifera), castor wax (catalytically hydrogenated castor oil),esparto wax (a byproduct of making paper from esparto grass, Macrochloatenacissima), Japan wax (a vegetable triglyceride, from the berries ofRhus and Toxicodendron species), jojoba oil (pressed from the seeds ofthe jojoba bush, Simmondsia chinensis), ouricury wax (from the Brazilianfeather palm, Syagrus coronata), rice bran wax (obtained from rice bran,Oryza sativa), and soy wax (from soybean oil). Examples of animal waxesinclude beeswax (produced by honey bees), Chinese wax (produced by thescale insect Ceroplastes ceriferus), lanolin (wool wax, from thesebaceous glands of sheep), and shellac wax (from the lac insect Kerrialacca).

Blends of waxes can be useful to incorporate materials properties fromthe different waxes. For example, paraffin wax, intermediate wax, and/ormicrocrystalline wax can be blended to provide a desired level ofplastic deformation at room temperature and dimensional stability athigher temperatures. Paraffin, intermediate and microcrystalline waxesare all fully saturated hydrocarbon mixtures with the formulaC_(n)H_(2n+2). Paraffin waxes predominately include straight-chainalkanes, microcrystalline waxes predominately include branched alkanesof higher molecular weight than the alkanes in paraffin wax, andintermediate waxes have components and properties intermediate to thoseof paraffin and microcrystalline waxes. The effect of branching is toreduce melting point and increase viscosity. In general, paraffin waxescomprise mostly linear C18 to C40 alkanes, intermediate waxes haveincreased branching and comprise mostly C25 to C60 alkanes, andmicrocrystalline waxes contain little or no linear alkanes but rathercomplex, branched C25 to C85 alkanes.

As a general rule, the properties of paraffin wax and microcrystallinewaxes can be generalized as follows:

Paraffin Wax Microcrystalline Wax Low melting Higher melting WhiteColored Hard Soft Brittle Malleable Translucent Opaque CrystallineAmorphous Glossy Adhesive

The one or more waxes comprising the wax fraction of wax-basedcompositions as disclosed herein are typically included in an amount ina range of about 40% to about 95% by weight, preferably in a range ofabout 50% to about 93% by weight, more preferably in a range of about60% to about 90% by weight, and most preferably in a range of about 70%to about 85% by weight of the wax-based composition.

The polymer fraction can include at least one type of polymer, examplesof which include one or more polymers selected from polyolefins,polyesters, polyurethanes, thermoplastic elastomers, thermosetelastomers, and mixtures thereof. Examples of polyolefins includepolyethylene (including high density polyethylene, HDPE), low densitypolyethylene, LDPE), or ultra low density polyethylene, ULDPE),polypropylene (PP), and polytetrafluoroethylene (PTFE) (e.g., TEFLON),thermoplastic polyolefins (e.g., thermoplastic polyethylene,thermoplastic polypropylene, thermoplastic olefins), and propylene-basedelastomers. Other synthetic polymers include ethylene-vinyl acetatecopolymer (EVA), ethylene-vinyl alcohol copolymer (EVAL), polyvinylacetate, polyvinyl alcohol, polyesters (such as polyethyleneterephthalate, or PETE), polycarbonates, methacrylates, acrylates,polyamides (e.g., nylon), polyurethanes, polyvinyl chloride (PVC),synthetic rubber, phenol formaldehyde resin (Bakelite), neoprene,polystyrene, polyacrylonitrile, PVB, silicone elastomers, andthermoplastic elastomers (e.g., olefin-based elastomers, such asethylene-, propylene- or butylene-based elastomers) (e.g., Engage™thermoplastic elastomers, Vistamaxx™ thermoplastic elastomers, such asVistamaxx™ 6102, Vistamaxx™ 6202, and Vistamaxx™ 3020, Duragrip® DGR6250CL, and Thermolast® M TM6LFT). Natural polymeric materials includeshellac, natural rubber, polysaccharides, cellulosic ethers, celluloseacetate, and proteins.

According to one embodiment, the polymer fraction can have high peroxidestability (i.e., so as to not cause decomposition of a peroxidebleaching agent) and/or good thermal stability (i.e., so as to yield astrip or tray that maintains its shape when exposed to elevatedtemperatures during shipping and storage).

The one or more polymers comprising the polymer fraction of wax-basedcompositions as disclosed herein are typically included in an amount ina range of about 5% to about 60% by weight, preferably in a range ofabout 7% to about 50% by weight, more preferably in a range of about 10%to about 40% by weight, and most preferably in a range of about 15% toabout 30% by weight of the wax-based composition.

When included, the one or more auxiliary components (e.g., plasticizers,flow modifiers, and/or fillers) can be included in an amount in a rangeof about 0.01% to about 5% by weight of the wax-based composition,preferably in a range of about 0.1% to about 4% by weight, and morepreferably in a range of about 1% to about 3% by weight of the wax-basedcomposition.

At least a portion of the wax fraction, polymer fraction and/orauxiliary component can be similar to and/or provided by the materialscontained in Parafilm®, which is sold in sheet form and which contains aproprietary blend of wax and polyolefin. Parafilm® M is a flexible sheetmaterial with a paper backing to prevent self-adhesion and is commonlyused to temporarily seal flasks or cuvettes in chemistry labs. Parafilm®F is commonly used in plant grafting. Parafilm® sheets typically softenat about 100° F. (or about 38° C.) and, if a Parafilm® sheet isthermoformed into a dental treatment tray, it begins to sag attemperatures of about 38° C. and above. As a result, oral treatmentstrips made using native Parafilm® as a barrier layer can becomecrinkled or shriveled at elevated temperatures during shipping andstorage (i.e., which can reach 50° C. or more). Moreover, oral treatmentstrips made using native Parafilm® as the barrier layer can becomeexcessively soft and gummy when placed in the mouth and exposed to bodytemperature over lengthy periods of time, permitting users to easilybite through and perforate the Parafilm® barrier layer, compromising itsability to function as a barrier to saliva.

Unexpectedly, however, when Parafilm® sheet material is cut into piecesand used as a feed material in an injection molding process, theresulting injection molded trays are thermally stable to a temperatureabove 40° C. (e.g., up to about 50-52° C. depending on the injectionmolding conditions). Therefore, the composition of “native” Parafilm® isapparently transformed into a new composition of matter when subject totemperatures and/or pressures associated with injection moldingprocesses, such as those described herein. In addition, Parafilm® can beused as a blending component together with other components disclosedherein to yield trays or strips having thermal stability at temperaturesof at least 40° C.

According to several embodiments, wax-based compositions are thermallystable (i.e., are dimensionally stable and resist significantdeformation) when formed into a flat sheet or a three-dimensionalarticle and heated to a temperature to which the sheet or article istypically subjected to during transport and storage. According to oneembodiment, the wax-based composition is thermally stable when heated toa temperature of at least 40° C., or at least about 42.5° C., or atleast about 45° C., or at least about 48° C., or at least about 50° C.,or at least about 52.5° C., or at least about 55° C., or at least about60° C., or at least about 65° C., or at least about 70°.

In addition, the wax-based composition can be plastically deformable.That is, the composition can be formed into a desired shape and thenretain that shape absent application of an external force. According toone embodiment, the wax-based composition is plastically deformable andnon brittle at room temperature (25° C.). In other words, the wax-basedcomposition can be configured into a desired shape without breaking orcracking and so as to retain that shape without heating to above roomtemperature. In other embodiments, the wax-based composition becomesplastically deformable at room temperature when extruded into a sheet orthermoformed or injection molded at elevated temperature into a desiredthree-dimensional article of a specified thickness. In some embodiments,the wax-based composition is semi-rigid at room temperature and becomesmore flexible and deformable when heated to above room temperature, suchas body temperature in the case of an oral treatment device thatincludes a wax-based barrier layer.

Depending on the relative concentrations of the wax and polymerfractions, the wax fraction may comprise a continuous phase and thepolymer fraction may comprise a disperse phase within the continuous waxphase. Alternatively, the polymer fraction may comprise a continuousphase and the wax fraction may comprise a disperse phase within thecontinuous wax phase. In some cases, it is possible for the wax andpolymer fractions to form an interpenetrating network without continuousand disperse phases.

An exemplary method of manufacturing a wax-based composition that issuitable for making sheets or articles that are thermally stable andplastically deformable includes: (1) combining a least one wax and atleast one polymer to form a mixture; and (2) processing the mixture toform a wax-based composition that is comprised of a wax fractionhomogeneously blended with a polymer fraction.

According to one embodiment, the at least one type of wax and the leastone type of polymer are combined and processed using an extruder (e.g.,a single screw or twin screw extruder). The extruder can form thewax-based composition into the form of a sheet having a desiredthickness. The sheet can be used as is or further shaped, such as bythermoforming, into a desired shape of an article of manufacture (e.g.,a dental treatment tray). Alternatively, the extruder can form thewax-based composition into a strand that is cut into individual pellets,which can then be further processed, such as by injection molding, toform a desired shape of an article of manufacture. Other mixingapparatus known in the art can be used to form wax-polymer blends, whichare then extruded, injection molded, or otherwise formed into a desiredshape.

Example extruders can include a plurality of zones (e.g., 10 zones),such as mixing, heating and pressuring zones. The wax, polymer andauxiliary materials can be fed separately into the extruder in differentzones or together in the same zone. For example, the one or more polymercomponents can be fed into zone 1, and the one or more wax componentscan be fed into zone 3. Auxiliary components, if used, can be fed intoone of these zones or a different zone. The zones can have similar ordifferent temperatures. In general, the materials fed into and mixedwithin the extruder can be subjected to one or more temperatures in arange of about 50° C. to about 225° C., preferably in a range of about55° C. to about 210° C. More preferably the materials in the earlierzones are subjected to a higher temperature in a range of about 135° C.to about 220° C. and in the later zones to a lower temperature in arange of about 50° C. to about 125° C. in another part of the extruder,most preferably to a higher temperature in the earlier zones in a rangeof about 140° C. to about 210° C. and to a lower temperature in thelater zones in a range of about 55° C. to about 120° C. The pressurewithin the extruder can be up to about 1000 psi, preferably up to about100 psi, more preferably up to about 50 psi, and most preferably in arange of about 1 to about 25 psi.

Example injection molding apparatus include a hopper, a barrel withfeeder screw, an injection nozzle, a valve gate, a mold cavity, and amold core. In an injection molding process, the wax-based compositioncan be subjected to one or more initial temperatures for melting orsoftening the composition in a range of about 40° C. to about 200° C.,preferably in a range of about 45° C. to about 150° C., and morepreferably in a range of about 50° C. to about 120° C. The feeder barrelcan have multiple heating zones of increasing temperature. In general,the highest temperature is reached at the valve gate. The softened ormelted composition is introduced into the mold cavity under pressure inorder to fill the mold cavity, such as at a pressure in a range of about1000 psi to about 50,000 psi, preferably in a range of about 2500 psi toabout 40,000 psi, more preferably in a range of about 5000 psi to about30,000 psi, even more preferably in a range of about 7500 psi to about20,000 psi, and most preferably in a range of about 10,000 psi to about15,000 psi. To yield a solidified injection molded article, the moldcore and cavity can have a reduced temperature in a range of about −10°C. to about 40° C., preferably in a range of about −5° C. to about 30°C., more preferably in a range of about 0° C. to about 25° C., even morepreferably in a range of about 2° C. to about 20° C., and mostpreferably in a range of about 3° C. to about 10° C.

III. Articles Made from Wax-Based Compositions

Examples of articles that can be made from wax-based compositions asdisclosed herein include, but are not limited to, sheets, oral treatmentstrips, sheets for sealing orifices, molded three-dimensional articles,and dental treatment trays. Sheet-like articles can be flat and areflexible and plastically deformable so as to be capable of being placedover an object and then wrapped around the object into a desiredconfiguration that is able to maintain its shape. In some cases, thesheets can “customizable” in order to include 3-dimensional features ofthe object around which it is wrapped. Similarly, moldedthree-dimensional articles can be plastically deformable so as to becapable of being placed over an object and then further adapted tobetter fit over the object and better conform to the three-dimensionalfeatures of the object around over which it is adapted.

According to several embodiments, flat or curved sheets are providedthat are plastically deformable at room temperature (25° C.) andthermally stable at temperatures of at least 40° C., or at least about42.5° C., or at least about 45° C., or at least about 48° C., or atleast about 50° C., or at least about 52.5° C., or at least about 55°C., or at least about 60° C., or at least about 65° C., or at leastabout 70° (e.g., at temperatures between 50-75° C. depending on theformulation). This permits sheet-like articles made form the wax-basedcompositions disclosed herein to be manufactured, transported and storedat temperatures of 50-75° C. or more without losing their desired shape.The sheets comprise a wax-based composition that includes a wax fractionand a polymer fraction homogeneously blended with the wax fraction. Thewax fraction includes at least one wax. The polymer fraction includes atleast one polymer. The sheet can be formed by extruding the wax-basedcomposition.

According to other embodiments, three-dimensional articles are providedthat are plastically deformable at room temperature (25° C.) andthermally stable to temperatures of at least 40° C., or at least about42.5° C., or at least about 45° C., or at least about 48° C., or atleast about 50° C., or at least about 52.5° C., or at least about 55°C., or at least about 60° C., or at least about 65° C., or at leastabout 70° (e.g., at temperatures between 50-75° C. depending on theformulation) and are therefore dimensionally stable at elevatedtemperatures.

IV. Oral Treatment Devices and Kits

Disclosed herein are oral treatment devices that include a barrier layercomprised of a wax-based composition and an oral treatment compositiondisposed adjacent to and/or impregnated within the barrier layer. Thebarrier layer can be in the form of a tray or strip. A dental treatmenttray typically includes at least one sidewall (e.g., at least a labialwall and optionally also a lingual wall) and a bottom wall adjacent toand extending laterally from the at least one sidewall (e.g., extendinglingually from the labial wall or forming a transition or bridge betweenlabial and lingual walls). Strip-like barriers and/or the at least onesidewall and bottom wall of a dental treatment tray comprise a wax-basedcomposition that includes at least one wax and at least one polymerhomogeneously blended with the wax. Oral treatment devices can be formedby thermoforming a wax-based sheet, injection molding a wax-basedcomposition, or any other appropriate method known in the art.

According to several embodiments, oral treatment devices made from thewax-based compositions disclosed herein are plastically deformable atroom temperature (25° C.) and thermally stable at temperatures of atleast 40° C., or at least about 42.5° C., or at least about 45° C., orat least about 47.5° C., or at least about 50° C., or at least about 53°C., or at least about 55° C., or at least about 60° C., or at leastabout 65° C., or, or at least about 70° C. (e.g., at temperaturesbetween 50-75° C. depending on the formulation) and are thereforedimensionally stable at elevated temperatures. This permits oraltreatment devices made form the wax-based compositions disclosed hereinto be manufactured, transported and stored at temperatures of 50-75° C.or more without losing their desired shape. Nevertheless, when placedinto a user's mouth, dental treatment trays and strip-like barrierlayers made from wax-based compositions disclosed herein can readilyconform the size and shape of a user's unique dentition (e.g., areself-customizable in a user's mouth). They can readily conform toocclusal surfaces yet resisting perforation because they are not undulysoftened at body temperatures.

According to one embodiment, the tray or strip can be non-customized anddevoid of features corresponding to user's unique dentition. Once placedin a user's mouth, the tray or strip can warm to body temperature, whichfacilitates the ability of the tray or strip to at least partiallyconform to the user's unique dentition and thereby become at leastpartially customized. For example, the tray or strip can be at leastpartially customized in the user's mouth using shaping forces such assuctioning, biting and/or finger pressure. According to anotherembodiment, the tray can be customized (e.g., using a stone model of auser's teeth to register indentations in the tray corresponding to theuser's unique dentition). Oral strips and trays are advantageouslyformulated so that it is difficult or impossible for a user to bitethrough the occlusal surface of the tray or strip in order to maintain abarrier to saliva.

Kits for providing oral treatments may include multiple oral treatmentdevices that include a wax-based barrier layer and one or morepre-applied oral treatment compositions. Alternatively, kits may includeone or more wax-based barrier layers and one or more oral treatmentcompositions that can be applied to the barrier layers by the user atthe time of use. Kits may include some barrier layers configured to fitover a person's upper teeth and other barrier layers configured to fitover a person's lower teeth.

Alternatively, a plurality of single-use, disposable customized dentaltreatment trays made from wax-based compositions as disclosed herein canbe provided to a user in a kit. According to one embodiment, the kit ofcustomized dental treatment trays permits the user to have the benefitof a new customized dental tray for every treatment event. Moreover,because of the plastically deformable nature of the wax-basedcomposition, trays made therefore can be more comfortable and betterfitting than professional custom-fitted trays.

A method of manufacturing a kit of single-use, disposable customizeddental treatment trays includes: (1) taking an impression of a user'steeth using an impression material; (2) making a stone model of theuser's teeth from the impression of the user's teeth; (3) providing aplurality of sheets comprised of a wax-based composition as disclosedherein; (4) thermoforming the sheets using the stone model to form theplurality of customized dental treatment trays; and (5) optionallytrimming away excess tray material to maximize appropriate size and fit.The single-use, disposable customized wax-based dental treatment trayscan be used in a kit that includes an oral treatment composition that isloaded into the trays by the user or they can be pre-loaded with an oraltreatment composition.

Regardless of its form, the barrier layer is typicallymoisture-resistant in order to protect the oral treatment compositionfrom saliva in a user's mouth. Because waxes and polymers tend to behydrophobic, wax-based compositions as disclosed herein will typicallybe moisture-resistant. The wax-based barrier layers will typically havea thickness in a range of about 0.025 mm to about 1.5 mm, or from about0.05 mm to about 1.25 mm, or from about 0.075 mm to about 1 mm, or fromabout 0.09 mm to about 0.75 mm, or from about 0.1 mm to about 0.5 mm, orfrom about 0.15 mm to about 0.35 mm.

According to one embodiment, the occlusal walls of example dentaltreatment trays can have a greater cross-sectional thickness than theone or more sidewalls (e.g., between about 20-100% thicker, or about30-75% thicker, or about 40-60% thicker). This provides severalbenefits, including the ability of the dental treatment trays to beself-customized to a user's teeth without the user biting through andperforating the occlusal wall. It can also increase dimensionalstability of the dental treatment trays by providing a more rigid baseto which the one or more sidewalls are attached without compromisingcomfort and fit. The occlusal wall is typically the last wall to contacta user's teeth during installation such that increased rigidity of theocclusal wall does not significantly decrease the ability of the thinnersidewall(s) to be customized or adapted to the user's labial and/orlingual tooth surfaces. Moreover, because the occlusal wall can beeasily self-customized to the user's occlusal tooth surfaces by biting,the user can readily self-customize the occlusal wall regardless ofincreased thickness. And in fact, increased thickness is most beneficialin the occlusal region, which is subjected to the greatest customizationforces (i.e., biting).

Another benefit of providing a thickened occlusal wall is that itfacilitates injection molding of relatively thin-walled dental treatmenttrays from the wax-based compositions disclosed herein. Because theocclusal wall of a molded tray is typically approximately midway betweenthe labial and lingual walls, the mold cavity in the regioncorresponding to a thickened occlusal wall will be wider than adjacentregions corresponding to the thinner labial and lingual walls. A widermold cavity in the middle region of the mold facilitates injectionmolding by providing better flow of the softened wax-based compositionthroughout the mold cavity.

Oral treatment compositions can include at least one active agent, atleast one tissue adhesion (or thickening) agent, a liquid or gelsolvent, carrier or vehicle into which the active agent and tissueadhesion agent are dispersed, and other components and adjuvents asdesired. The treatment composition may comprise continuous ordiscontinuous beads or layers positioned so as to contact at least aportion of a person's tooth surfaces and/or gums. Treatment compositionscan have a consistency of a liquid, gel, sticky viscous gel, putty, orsolid. Solids and putties can become more sticky and adhesive to teethand/or gums when moistened with water or saliva. In some cases, the maindifference between a “gel” and a “putty” or “solid” is the level ofsolvent or carrier within the composition. In general, the greater theconcentration of solvent or carrier relative to the tissue adhesiveagent, the less viscous is the composition. The lower the concentrationof solvent or carrier relative to the tissue adhesion agent, the moreviscous, putty-like or solid is the composition.

Examples of active agents for oral treatment compositions include dentalbleaching agents, desensitizing agents, remineralizing agents,antimicrobial agents, anti-plaque agents, anti-tartar agents, gingivalsoothing agents, anesthetics, anti-oxidants, and mouth fresheningagents. Examples of dental bleaching agents include aqueous hydrogenperoxide, carbamide peroxide, metal perborates (e.g., sodium perborate),metal percarbonates (e.g., sodium percarbonate), metal peroxides (e.g.,calcium peroxide), metal chlorites and hypochlorites, peroxy acids(e.g., peroxyacetic acid), and peroxy acid salts.

Bleaching agents within dental bleaching compositions according to theinvention can have any desired concentration, e.g., between 1-90% byweight of the dental bleaching composition. The concentration of thedental bleaching agent can be adjusted depending on the intendedtreatment time for each bleaching session. The bleaching agent ispreferably included in an amount in a range of about 1% to about 60% byweight, more preferably in a range of about 3% to about 40% by weight,and most preferably in a range of about 5% to about 30% by weight. Whena dental bleaching agent is used, the materials used to make thewax-based composition can be selected so as to not prematurely reactwith and destabilize the bleaching agent.

Examples of desensitizing agents include potassium nitrate, otherpotassium salts, citric acid, citrates, and sodium fluoride. Examples ofremineralizing agents in sodium fluoride, stannous fluoride, sodiummonofluorophosphate, and other fluoride salts. Examples of antimicrobialagents and preservatives include chlorhexidine, triclosan, sodiumbenzoate, parabens, tetracycline, phenols, cetyl pyridinium chloride,and benzalkonium chloride. An example of an anti-plaque or anti-tartaragent is pyrophosphate salts. Examples of gingival soothing agentsinclude aloe vera, mild potassium nitrate, and isotonic solution-formingsalts. Examples of anesthetics include benzocaine and lidocaine.Examples of anti-oxidants include vitamin A, vitamin C, vitamin E, othervitamins, and carotene. Examples of mouth freshening agents includecamphor, oil of wintergreen, peppermint, spearmint, and methylsalicylate.

Tissue adhesion agents, tackifying agents, or thickening agents caninclude a wide variety of hydrophilic polymers. Examples includepolyvinyl pyrrolidone (PVP), PVP-vinyl acetate copolymers,carboxypolymethylene (e.g., CARBOPOL, sold by Novean, Inc.),polyethylene oxide (e.g., POLYOX, made by Union Carbide), polyacrylicacid polymers or copolymers (e.g., PEMULEN, sold by Novean, Inc.),polyacrylates, polyacrylamides, copolymers of polyacrylic acid andpolyacrylamide, carboxymethylcellulose, carboxypropylcellulose,cellulosic ethers, polysaccharide gums, proteins, and the like. Examplesof PVPs include Kollidon 30, a polyvinyl pyrrolidone polymer sold byBASF having a molecular weight of 50,000, Kollidon VA 60, a polyvinylpyrrolidone polymer having a molecular weight of 60,000, and Kollidon 90F, a polyvinyl pyrrolidone polymer having a molecular weight of 1.3million.

In the case where the oral treatment composition is a gel, the one ormore tissue adhesion agents are preferably included in an amount in arange of about 1% to about 50% by weight of the treatment gel, morepreferably in a range of about 3% to about 30% by weight, and mostpreferably in a range of about 5% to about 20% by weight.

In the case where the oral treatment composition is a putty or solid,the one or more tissue adhesion agents are preferably included in anamount in a range of about 10% to about 90% by weight of thesubstantially solid treatment composition, more preferably in a range ofabout 20% to about 80% by weight, and most preferably in a range ofabout 40% to about 75% by weight.

Liquids and gels, including sticky viscous gels, may include one or moreliquid or gel, solvents, carriers or vehicles into which the activeagent, tissue adhesion agent, and other components are dissolved ordispersed. Examples of liquid or gel solvents, carriers or vehiclesinclude water, alcohols (e.g., ethyl alcohol), and polyols (e.g.,glycerin, sorbitol, mannitol, other sugar alcohols, propylene glycol,1,3-propandiol, polyethylene glycol, polyethylene oxide, andpolypropylene glycol).

For solids or stiff putties, the concentration of solvent, carrier orvehicle will typically be attenuated compared to treatment gels. Whereit is desired to convert a gel into a putty or solid composition, it maybe advantageous to include one or more volatile solvents that can beremoved by evaporation (e.g., water, alcohols, acetone, and otherorganic solvents). Because of the affinity of hydrophilic polymers forwater, even treatment compositions that appear to be solid may include asignificant amount of bound water (e.g., up to about 10% or more byweight of the treatment composition). In the case where the treatmentcomposition has the consistency of a highly viscous or stiff putty, thecomposition will generally include a solvent, carrier or vehicle thatacts as a plasticizer or softening agent.

Oral treatment compositions may optionally include other components asdesired to yield treatment compositions having desired properties.Examples include bleaching agent stabilizers (e.g., EDTA, salts of EDTA,citric acid and its salts, phosphoric acid and its salts,phenolphosphonic acid and its salts, gluconic acid and its salts, alkalimetal pyrophosphates, alkali metal polyphosphates, and alkyl sulfates),neutralizing agents (e.g., sodium hydroxide and triethanolamine),inorganic thickening agents (e.g., fumed silica), colorants, flavorants,sweeteners, and the like.

According to one embodiment, oral treatment devices can have ahorseshoe-shaped longitudinal profile and a trough with a U-shaped crosssection, as in conventional bleaching trays. Alternatively, oraltreatment devices can have barrier layers with other shapes, such asflat strips that are rectangular or contoured to fold around and fitover a user's teeth.

Exemplary dental treatment devices 100, 100′ in the form of a tray areillustrated in FIGS. 1A and 1B. FIG. 1A is a perspective view of an oraltreatment device 100 comprising a wax-based barrier layer 102 having afront side wall 104, a rear side wall 106, and a horseshoe shaped bottomwall 108 that together define a trough 110 having a generally U-shapedcross section throughout the horseshoe. Disposed within trough 110 is anoral treatment composition 112 that can be a gel, such as a sticky,viscous gel, which can assist in reliably holding the dental treatmenttray in proper position over a user's teeth during use. Oral treatmentcomposition 112 may have a consistency ranging from a gel, a stickyviscous gel, to a solid treatment composition. Oral treatmentcomposition 112 can be a viscous gel having a cross-sectional diameteror thickness in a range of about 1 mm to about 5 mm, more preferably ina range of about 2 mm to about 4 mm. The gel can be a continuous bead ofcomposition.

FIG. 1B depicts an oral treatment device 100′ that includes a wax-basedbarrier layer 102 in the form of a dental tray having a horseshoe shapewith a substantially U-shaped cross section. Barrier layer 102 includesfront sidewall 104, rear sidewall 106, and bottom wall 108 that togetherdefine a trough 110 having a general U-shaped cross section. Withintrough 110 is an oral treatment composition 112′ that substantiallycovers the interior walls rather than being a bead of composition. Oraltreatment composition 112′ may be a gel, a sticky viscous gel, a putty,or a solid composition. Treatment composition 112′ is preferably a stiffputty or solid having a thickness in a range of about 0.2 mm to about 2mm, more preferably in a range of about 0.5 mm to about 1 mm.

FIGS. 2A and 2B depict oral treatment devices 200, 200′, each of whichinclude a barrier layer 202 having a front sidewall 204, a rear sidewall206, and a bottom wall 208 that together define a trough 210 into whicheither a bead of treatment composition 212 (FIG. 2A) or a continuouslayer of treatment composition 212′ (FIG. 2B) is disposed. In addition,oral treatment devices 200, 200′ include a first notch 214 in frontsidewall 204 and a second notch 216 in rear sidewall 206. Notches 214and 216 assist the oral treatment devices 200, 200′ in conforming tovariously sized and shaped dental arches.

The FIGS. 3A and 3B depict oral treatment devices 300, 300′ withfeatures that assist the barrier layers in better conforming to the sizeand shape of variously dental arches. Instead of continuous sidewalls,oral treatment devices 300, 300′ includes a barrier layer 302 having afront sidewall 304, a rear sidewall 306, and a bottom wall 308interconnecting front sidewall 304 and rear sidewall 306. Rear sidewall306 further includes a first rear sidewall section 306 a that includes afirst cut or discontinuity 307 and a second rear sidewall section 306 bseparated from first rear sidewall section 306 a by second cuts ordiscontinuities 309. The first rear sidewall section 306 a is configuredto wrap around and lie adjacent to inner surfaces of a person's incisorsand canines. Second rear sidewall section 306 b is configured to wraparound and contact inner surfaces of a person's bicuspids and optionallyone or more molars.

Cuts or discontinuities 309 between first and second sidewall sections306 a, 306 b facilitate good fit against a person's incisors andcanines, particularly at the junction of the canines and bicuspids. Cutsor discontinuities 309 compensate for the abrupt difference in widthbetween a person's bicuspids adjacent to the second rear sidewallsection 306 b and the canines adjacent to the first rear sidewallsection 306 a. Discontinuity or cut 307 in first sidewall section 306 afurther assists in conforming first sidewall section 306 a to innersurfaces of a person's incisors and canines.

FIG. 3A further shows a continuous bead of an oral treatment composition312 within an interior region or trough defined by front sidewall 304,rear sidewall 306, and bottom wall 308. FIG. 3B alternatively depicts asubstantially continuous layer of an oral treatment composition 312′disposed within an interior region or trough defined by front sidewall304, rear sidewall 306, and bottom wall 308.

To protect oral treatment devices from contaminants during storage andprior to use, treatment devices can be packaged within a sealedcontainer or package. As illustrated in FIGS. 4A and 4B, exemplarysealed oral treatment packages 400, 400′ include an oral treatmentdevice 402, 402′ (e.g., dental treatment trays) sealed within aprotective package 404, 404′. Protective packages 404, 404′ includes arigid support layer 406, 406′ and a peelable cover 408, 408′. When it isdesired to use oral treatment device 402, 402′, the peelable cover 408,408′ is removed and treatment device 402, 402′ is removed or separatedfrom support layer 406, 406′.

FIGS. 5A and 5B depict an embodiment of an oral treatment device in theform of a treatment strip rather than a treatment tray. Oral treatmentstrip 500 includes a strip of wax-based material 502, which is initiallysubstantially flat and can optionally have rounded corners. Strip ofwax-based material 502 may be a single layer of wax-based materialcomprised of a homogeneous blend of wax and polymer. Coated onto and/orimpregnated into strip of wax-based material 502 is an oral treatmentcomposition 504. Oral treatment composition 504 can be a homogeneousmaterial, uniformly and continuously coated onto strip of wax-basedmaterial 502.

FIGS. 6A and 6B illustrate an oral treatment device 600 applied to andclosely conforming to a surface of a tooth 602. Oral treatment device600 may include a barrier layer in the form of a dental treatment trayor strip-like sheet that is wrapped around tooth 602 to form a tray-likeconfiguration. Oral treatment device 600 also includes an oral treatmentcomposition that is able to provide a desired treatment to teeth and/orgums. While oral treatment device 600 is shown so that it only coverstooth 602 and not adjacent soft oral tissue 604, it is within the scopeof the disclosure for the oral treatment device 600 to extend beyondgingival margin 606 and at least partially overlap soft oral tissue 604.

FIGS. 7A-7E illustrate various embodiments of strip-like barrier layers,which can be placed over a user's teeth and/or gums and adapted so as towrap around and contact both labial and lingual surfaces. FIG. 7Aillustrates an embodiment of a strip of wax-based material 700 that issubstantially trapezoidal in shape. Strip 700 has a first side 701, asecond side 702, a third side 703, and a fourth side 704. First side 701and second side 702 are generally straight sides that angle inward fromfourth side 704 toward third side 703. Third side 703 can be concave andshorter then fourth side 704, while fourth side 704 can be convex. Inuse, fourth side 704 can be placed adjacent to the gingival margin at anintersection between a user's teeth and gums. A fold line 705 may beincluded in strip 700, which extends from first side 701 to second side702. Fold line 705 may be located closer to third side 703 or fourthside 704 depending on the desired size and shape of the device whenfolded during use. Fold line 705 may be determined by the size of auser's teeth and the manner of placement of the oral treatment strip onthe user's teeth. Third side 703 will be positioned adjacent to thelingual surfaces of the user's teeth upon folding strip 700 along foldline 705.

FIG. 7B illustrates another embodiment of a strip of wax-based material720 that is substantially trapezoidal in shape with stair-stepped sides.Strip 720 has a first side 721, a second side 722, a third side 723, anda fourth side 724. Third side 723 can be concave and shorter then fourthside 724. Fourth side 724 can be convex. First side 721 and second side722 are both stair step sides that include inner corners 726, 727,respectively. A fold line 725 typically extends between inner corners726, 727 of the stair steps in first side 721 and second side 722,respectively.

FIG. 7C illustrates an alternative embodiment of a strip of wax-basedmaterial 730 that is substantially rectangular in shape withstair-stepped sides. Strip 730 includes a first side 731, a second side732, a third side 733, and a fourth side 734. First side 731 and secondside 732 are both stair step sides that include inner corners 726, 727,respectively. A fold line 735 extends from the corners 736 and 737 ofthe stair steps in first side 731 and second side 732, respectively.Fold line 35 can be placed over occlusal surfaces of a user's teeth,which permits the strip 700 to fold around and over both the labial andlingual surfaces of the user's teeth. Strip 700 can be placed so thatthe user's two canine teeth are just outside of corners 736 and 737.Fourth side 734 can be located close to the gingival margin of the frontside of a user's teeth. Third side 733 will be located along the lingualsurface of the user's teeth.

FIG. 7D illustrates an alternative embodiment of a strip of wax-basedmaterial 740 that is substantially rectangular in shape but with notchedsides. Strip 740 has a first side 741, a second side 742, a third side743, and a fourth side 744. Third side 743 and fourth side 744 are bothsubstantially straight sides and can be the same length. First side 741and second side 742 include notches 746, 747, respectively, which enablethe occlusal surfaces of a user's canine teeth to not be covered whenthe strip 740 is placed over the user's teeth. A fold line 745 canextends from notch 746 in first side 741 to notch 747 in second side742. Notches 746, 747 can have sideways V shapes as shown. However, thenotches can be of any desired shape, including rectangular, square, semicircular, oval, and the like and that allow the tips of the canine teethto not be covered by strip 740 when worn over the user's teeth.

FIG. 7E illustrates an alternative embodiment of a strip of wax-basedmaterial 750 that is substantially rectangular in shape but with a foldline 755 between sides 756 and 757 in order to facilitate folding aroundocclusal edges of a user's teeth during installation.

V. Examples

Following are examples of wax-based compositions that may be used tomanufacture oral treatment devices, including dental treatment trays andstrip-like barrier layers. The exemplary formulations and manufacturingconditions are given by way of example, and not by limitation. Unlessotherwise indicated, all percentages are by weight.

Comparative Example

A sheet of Parafilm® M was thermoformed into a dental treatment tray byheating the sheet to a softening temperature and then vacuum forming thesoftened sheet over a die having the shape of the dental treatment tray.The resulting dental treatment tray was able to maintain its shape as atray at room temperature and could be used as a barrier layer in an oraltreatment tray. However, the tray lacked thermal stability and lostdimensional stability at temperatures of about 100° F. (about 38° C.) orabove. As a result, it was determined that dental treatment trays madeby thermoforming Parafilm® M were unsuitable for use in manufacturingoral treatment devices that are subjected to higher temperatures duringshipping and storage (i.e., up to 50° C.).

The dental trays in the following Examples were or are manufactured byinjection molding a wax-based composition as described below. Thewax-based composition of each example was or is initially formed byintroducing the materials into a twin screw extruder having multiplezones, heating and mixing the materials in the extruder, extruding thecomposition into a strand, cooling the extruded strand in a water bath,and chopping the strand in to pellets. The pellets were or are then fedinto an injection molding machine and injection molded into dentaltrays. The injection molding machine was configured to initially heatthe wax-based composition prior to introduction into the mold cavity andthen cool the material to form the solidified trays. The injectionmolded trays had an average sidewall thickness of about 0.007-0.008 mil(about 0.18-0.2 mm), with thickened occlusal surfaces of about0.010-0.013 mils (25-33 mm)

Examples 1-10

Example Component 1 2 3 4 5 6 7 8 9 10 Parafilm ® M¹ 100% 35% 30% 50%90% 95% 25% 25% 25% 25% Paraffin wax 65% 65% 65% 65% 65% (mp = 167° F.)Paraffin wax 70% (mp = 149° F.) Paraffin wax 50% (mp = 181° F.)Thermoplastic 10%  5% polyolefin elastomer Distilled wax² 10% Distilledwax³ 10% Distilled wax⁴ 10% Distilled wax⁵ 10% ¹Proprietary blend ofparaffin wax and polyolefin. ²Congealing point: 129.5-135.1° C.; startto open point: 115.6-121.2° C.; terminal point: 129.5-135.1° C.; volumeof expansion: 16-18%; travel: 6.37-6.89 mm ³Congealing point: 124-129.5°C.; start to open point: 107.3-112.9° C.; terminal point: 126.8-132.3°C.; volume of expansion: 16-18%; travel: 6.37-6.89 mm ⁴Congealing point:105.1-106.2° C.; start to open point: 98.4-100.0° C.; terminal point:114.5-116.2° C.; volume of expansion: 14-16%; travel: 5.88-6.37 mm⁵Congealing point: 100-101.2° C.; start to open point: 89.0-90.1° C.;terminal point: 105.6-106.8° C.; volume of expansion: 14-16%; travel:5.88-6.37 mm

Dental treatment trays made according to Examples 1-10 had varyinglevels of thermal stability, plastic deformability, and comfort. All hadbetter thermal stability compared to the thermoformed tray of theComparative Example, even the injection molded tray of Example 1, whichwas made by injection molding the composition of Parafilm® M. By way ofcomparison, the tray of Example 1, made by injection molding 100%Parafilm® M, was dimensionally stabile up to a temperature of about50-52° C. As the amount of Parafilm® M was reduced and replaced by othercomponents, such as paraffin wax, thermoplastic polyolefin elastomerand/or distilled wax, the temperature stability of the trays increasedas did the ability of the trays to be plastically deformable in a user'smouth.

Examples 11-19

Example Component 11 12 13 14 15 16 17 18 19 Parafilm ® M¹ 25% 25% 25%25% 25% 25% 25% 25% 25% Paraffin Wax 65% 65% 65% 65% 64% 65% 64% 65% (mp= 167° F.) Distilled wax²  5%  8% Distilled wax³  5%  5%  5%  3%  5%  3%Distilled wax⁴  5% Distilled wax⁵  5%  5%  8% Distilled wax⁶ 10%Distilled wax⁷ 10% ¹Proprietary blend of paraffin wax and polyolefin.²Congealing point: 129.5-135.1° C.; start to open point: 115.6-121.2°C.; terminal point: 129.5-135.1° C.; volume of expansion: 16-18%;travel: 6.37-6.89 mm ³Congealing point: 124-129.5° C.; start to openpoint: 107.3-112.9° C.; terminal point: 126.8-132.3° C.; volume ofexpansion: 16-18%; travel: 6.37-6.89 mm ⁴Congealing point: 100-101.2°C.; start to open point: 89.0-90.1° C.; terminal point: 105.6-106.8° C.;volume of expansion: 14-16%; travel: 5.88-6.37 mm ⁵Congealing point:95.1-96.2° C.; start to open point: 89.5-90.6° C.; terminal point:100.6-101.7° C.; volume of expansion: 14-16%; travel: 5.88-6.37 mm⁶Congealing point: 80.1-81.2° C.; start to open point: 74.5-75.6° C.;terminal point: 85.6-86.7° C. volume of expansion: 14-16%; travel:5.88-6.37 mm ⁷Congealing point: 109-110.6° C.; start to open point:104-105.6° C.; terminal point: 125.7-127.9° C.; volume of expansion:15-17%; travel: 6.13-6.63 mm

Dental treatment trays made according to Examples 11-19 had varyinglevels of thermal stability, plastic deformability, and comfort. Thetrays made according to Examples 11-19 had improved thermal stabilitycompared to the tray of the Comparative Example. Reducing the amount ofParafilm® M and replacing it with other components, such as paraffin waxand/or distilled wax, increased temperature stability and the ability ofthe trays to be plastically deformable in a user's mouth.

Examples 20-28

Example Component 20 21 22 23 24 25 26 27 28 Propylene-based 22% 20% 20%20% 15% 30% 15% elastomer¹ Propylene-based 22% elastomer²Propylene-based 22% elastomer³ Microcrystalline 44% 44% 44% 80% 60% 40%55% 40% 40% Wax⁴ Paraffin Wax⁵ 33% 33% 33% 20% 40% 30% 30% 45% ¹Density:0.862 g/cm³; MFR (230° C./2.16 kg): 3.0 g/10 min; ethylene content: 16.0wt %; durometer hardness (Shore A, 15 sec, 23° C.); 67; flexural modulus(23° C.): 11.4 MPa; tensile set (23° C.): 13%; tensile stress at 100%(23° C.): 2.12 MPa; tensile stress at 300% (23° C.): 2.68 MPa; tensilestrength at break (23° C.): 13.9 MPa; elongate at break (23° C.): 860%;tear strength (23° C.): 31.0 kN/m; viscat softening temp: 59.0° C.²Density: 0.861 g/cm³; melt index: 7.4 g/10 min; MFR (230° C./2.16 kg):18 g/10 min; ethylene content: 15.0 wt %; durometer hardness (Shore A,15 sec, 23° C.); 61; flexural modulus (23° C.): 11.0 MPa; tensile set(23° C.): 13%; tensile stress at 100% (23° C.): 1.70 MPa; tensile stressat 300% (23° C.): 2.10 MPa; tensile strength at break (23° C.): >7.29MPa; elongate at break (23° C.): >2000%; tear strength (23° C.): 33.0kN/m; viscat softening temp: 48.0° C. ³Density: 0.874 g/cm³; melt index:0.90 g/10 min; MFR (230° C./2.16 kg): 2.2 g/10 min; ethylene content:10.5 wt %; Shore A hardness (23° C.); 85; flexural modulus (23° C.):60.4 MPa; tensile set (23° C.): 49%; tensile stress at 100% (23° C.):4.40 MPa; tensile stress at 300% (23° C.): 4.50 MPa; tensile strength atbreak (23° C.): 17.8 MPa; elongate at break (23° C.): 1800%; tearstrength (23° C.): 64 kN/m; viscat softening temp: 70.0° C.; peakcrystallization temp: 65.0° C.; crystallinity, Hf: 28.0 J/g;crystallization peak, Tc: 64° C. ⁴Drop melt point: 88.9° C. min;kinematic viscosity (100° C.): 16.5 cSt min; oil content: 1.8 wt % max;flash point: 260° C.; ASTM color: 0.5 max; odor: 2 max; needlepenetration (25° C.): 10 dmm max ⁵Congealing point: 66.7-74.4° C.;kinematic viscosity (100° C.): 5.7-7.9 cSt; oil content: 1.0 wt % max;saybolt color: +25 min; needle penetration (25° C.): 18 dmm max;specific gravity (25° C.): 0.927

Dental treatment trays made according to Examples 20-28 providedimproved thermal stability and plastic deformation compared to the traymade according to the Comparative Example.

Examples 29-38

Example Component 29 30 31 32 33 34 35 36 37 38 Propylene-based 20% 20%20% 40% 30% 30% 30% 35% 25% 15% elastomer¹ Microcrystalline 40% 60% 20%30% 35% 50% 20% 33% 38% 43% Wax²) Paraffin Wax³ 40% 20% 60% 30% 35% 20%50% 33% 38% 43% ¹Density: 0.861 g/cm³; melt index: 7.4 g/10 min; MFR(230° C./2.16 kg): 18 g/10 min; ethylene content: 15.0 wt %; durometerhardness (Shore A, 15 sec, 23° C.); 61; flexural modulus (23° C.): 11.0MPa; tensile set (23° C.): 13%; tensile stress at 100% (23° C.): 1.70MPa; tensile stress at 300% (23° C.): 2.10 MPa; tensile strength atbreak (23° C.): >7.29 MPa; elongate at break (23° C.): ²Drop melt point:88.9° C. min; kinematic viscosity (100° C.): 16.5 cSt min; oil content:1.8 wt % max; flash point: 260° C.; ASTM color: 0.5 max; odor: 2 max;needle penetration (25° C.): 10 dmm max ³Congealing point: 66.7-74.4°C.; kinematic viscosity (100° C.): 5.7-7.9 cSt; oil content: 1.0 wt %max; saybolt color: +25 min; needle penetration (25° C.): 18 dmm max;specific gravity (25° C.): 0.927

Dental treatment trays made according to Examples 29-38 providedimproved thermal stability and plastic deformation compared to the traymade according to the Comparative Example.

Examples 39-48

Example Component 39 40 41 42 43 44 45 46 47 48 Thermoplastic 20% 20%20% 40% 30% 30% 30% 35% 25% 22% elastomer¹ Microcrystalline 40% 60% 20%30% 35% 50% 20% 33% 38% 39% Wax²) Paraffin Wax³ 40% 20% 60% 30% 35% 20%50% 33% 38% 39% ¹Specific Gravity: 885; density: 0.883 g/cm³; MFR (190°C./2.16 kg): 31 g/10 min; durometer hardness (Shore A, 5 sec): 50;tensile stress (100% strain): 1.54 MPa; tensile stress (300% strain):2.27 MPa; tensile strength (yield): 6.85 MPa; tensile elongation(break): 800%; tear strength (Die C): 23.6 kN/m; melt viscosity (374°F., 200 sec⁻¹): 136 Pa-s. ³Drop melt point: 88.9° C. min; kinematicviscosity (100° C.): 16.5 cSt min; oil content: 1.8 wt % max; flashpoint: 260° C.; ASTM color: 0.5 max; odor: 2 max; needle penetration(25° C.): 10 dmm max ⁴Congealing point: 66.7-74.4° C.; kinematicviscosity (100° C.): 5.7-7.9 cSt; oil content: 1.0 wt % max; sayboltcolor: +25 min; needle penetration (25° C.): 18 dmm max; specificgravity (25° C.): 0.927

Dental treatment trays made according to Examples 39-48 providedimproved thermal stability and plastic deformation compared to the traymade according to the Comparative Example.

Examples 49-58

Example Component 49 50 51 52 53 54 55 56 57 58 Thermoplastic 20% 20%20% 40% 30% 30% 30% 35% 25% 22% elastomer¹ Microcrystalline 40% 60% 20%30% 35% 50% 20% 33% 38% 39% Wax³) Paraffin Wax⁴ 40% 20% 60% 30% 35% 20%50% 33% 38% 39% ¹Density: 0.890 g/cm ; tensile stress (yield): 10.6 MPa;tensile elongation: 780%; tear strength 16 kN/m; compression set (23°C.): 18%; compression set (70° C.): 35%; compression set (100° C.): 52%;Shore A hardness: 60 ²Drop melt point: 88.9° C. min; kinematic viscosity(100° C.): 16.5 cSt min; oil content: 1.8 wt % max; flash point: 260°C.; ASTM color: 0.5 max; odor: 2 max; needle penetration (25° C.): 10dmm max ³Congealing point: 66.7-74.4° C.; kinematic viscosity (100° C.):5.7-7.9 cSt; oil content: 1.0 wt % max; saybolt color: +25 min; needlepenetration (25° C.): 18 dmm max; specific gravity (25° C.): 0.927Dental treatment trays made according to Examples 49-58 providedimproved thermal stability and plastic deformation compared to the traymade according to the Comparative Example.

Example 59

Any of the compositions of Examples 2-58 is extruded or otherwise formedinto a sheet having a thickness so as to be thermoformable and thenformed into a tray using a thermoforming technique known in the art. Thetrays formed according to Example 59 provide improved thermal stabilityand plastic deformation compared to the tray made according to theComparative Example.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. An oral treatment device, comprising: a flexiblebarrier layer sized and configured to be placed over at least a portionof a user's teeth and formed from a wax-based composition, the wax-basedcomposition comprising: 50% to 93% by weight of a wax fractioncomprising paraffin wax and microcrystalline wax; and 7% to 50% byweight of a thermoplastic elastomer.
 2. The oral treatment device ofclaim 1, wherein the barrier layer is thermally stable to a temperatureof at least 45° C.
 3. The oral treatment device of claim 1, wherein thebarrier layer forms a three-dimensional tray comprising at least onesidewall and a bottom wall adjacent to and extending laterally from theat least one sidewall.
 4. The oral treatment device of claim 1, whereinthe barrier layer forms a strip.
 5. The oral treatment device of claim1, wherein the wax fraction is included in a range of 60% to 90% byweight of the wax-based composition.
 6. The oral treatment device ofclaim 1, wherein the wax fraction is included in a range of 75% to 85%by weight of the wax-based composition.
 7. The oral treatment device ofclaim 1, wherein the wax fraction is homogenously blended with thethermoplastic elastomer.
 8. The oral treatment device of claim 1,wherein the thermoplastic elastomer is included in a range of 15% to 30%by weight of the wax-based composition.
 9. The oral treatment device ofclaim 1, wherein the thermoplastic elastomer is included in a range of10% to 40% by weight of the wax-based composition.
 10. The oraltreatment device of claim 1, wherein the thermoplastic elastomercomprises a thermoplastic polyolefin elastomer.
 11. The oral treatmentdevice of claim 1, wherein the thermoplastic elastomer comprises apropylene-based elastomer.
 12. The oral treatment device of claim 1,wherein the wax-based composition comprises the paraffin wax, themicrocrystalline wax, and the thermoplastic elastomer and one or moreauxiliary components selected from plasticizers, flow modifiers andfillers.
 13. The oral treatment device of claim 1, further comprising aperoxide bleaching agent disposed on the barrier layer.
 14. The oraltreatment device of claim 13, wherein the barrier layer comprises adental treatment tray having an arch shape and one or more sidewallsextending from a bottom wall of the dental treatment tray.
 15. The oraltreatment device of claim 13, wherein the thermoplastic elastomercomprises a propylene-based elastomer having high peroxide stability soas not to cause decomposition of the peroxide bleaching agent.
 16. Amethod of manufacturing an oral treatment device, comprising: blendingparaffin wax, microcrystalline wax, and thermoplastic elastomer to forma wax-based composition comprising 40% to 95% by weight of a waxfraction comprising the paraffin wax and the microcrystalline wax, and5% to 60% by weight of the thermoplastic elastomer; and injectionmolding the wax-based composition into a flexible barrier layer sizedand configured to be placed over at least a portion of a user's teeth.17. The method of claim 16, wherein the blending comprises processingthe paraffin wax, the microcrystalline wax and the thermoplasticelastomer using an extruder to form the wax-based composition into asheet or strand.
 18. The method of claim 16, wherein the injectionmolding comprises injection molding the wax-based composition into atray having an arch shape and one or more sidewalls extending from abottom wall of the dental treatment tray.
 19. The method of claim 18,wherein the injection molding comprises forming the tray having athickness in a range of from 0.025 mm to 1.5 mm.
 20. The method of claim16, further comprising disposing an oral treatment composition on thebarrier layer.
 21. The oral treatment device of claim 1, wherein thebarrier layer is plastically deformable at a temperature of 25° C. 22.The oral treatment device of claim 21, wherein the plasticallydeformable barrier layer becomes more flexible and deformable whenheated to temperatures of greater than 25° C. so as to at leastpartially conform to the user's teeth when placed into the user's mouth.23. The oral treatment device of claim 1, wherein the barrier layer hasa thickness in a range of from 0.025 mm to 1.5 mm.
 24. An oral treatmentdevice, comprising: a flexible dental treatment tray sized andconfigured to be placed over at least a portion of a user's teeth,having a thickness in a range of from 0.025 mm to 1.5 mm, and that isformed by injection molding from a wax-based composition comprising: 40%to 95% of by weight of a wax fraction comprising paraffin wax andmicrocrystalline wax; and 5% to 60% by weight of a thermoplasticelastomer.